Electric clothes dryers typically provide for warmed air flow through a rotating drum to remove moisture from clothing articles tumbling in the drum. The air is warmed by passing over energized electrical heating elements supported within a heater housing. In one construction of electrical clothes dryers, the rotating drum is closed at one end by a rear end head. This rear end head is provided with a pattern of apertures through which air passes into the rotating drum. In one embodiment, the rear end head rotates with the drum and in another embodiment the rear end head remains stationary while the cylindrical outer wall of the drum rotates.
A heater assembly is typically mounted within the dryer adjacent the rear end head of the drum. In the embodiment where the rear end head rotates with the drum, the heater assembly has been known to comprise a circular stationary rear support wall mounted to the rear wall of the dryer. This circular stationary wall typically has a peripheral flange that extends towards the rear end head of the drum and that is spaced from the rear end head to provide an air gap. A housing is formed between the rear end head, the rear support wall and the peripheral flange. In the past, an electrical heating element in the form of a helical coil has been mounted to the rear support wall of the clothes dryer assembly. This mounting has been accomplished by the use of metal brackets with insulators attached to the rear support wall, or more recently, by ceramic brackets attached to the rear wall of the housing. The brackets have typically been placed in two arcuate patterns whereby the coils are stretched from bracket to bracket forming a generally arcuate shape. While this heater arrangement has been quite effective, the assembly of the brackets onto the rear wall and then subsequent stretching of the heater coils onto the brackets about the heater rear wall is a relatively labour intensive operation. Further, in certain instances the number of coil rotations between brackets may not be consistent due to human operator error. This has been known to result in an uneven heat distribution.
In other heater assembly embodiments, it is known to mount coils to mica support insulating plates. Further, it is known to support a zigzag configured electrical heating element also known as meander-shaped windings. Such a heater configuration is disclosed in U.S. Pat. No. 4,845,345 issued Jul. 4, 1989. In this configuration, zigzag heating elements extend outwardly between apertures in a first mica plate. The first mica plate is secured to a second mica plate and portions of the heating element are held in place between the first and second mica plates. While this configuration results in a highly stable heating element which is simple to manufacture, this heating element configuration does not lend itself readily to use in electric clothes dryers.